Art Evolution: Borne posted a YouTube clip of the many rough drafts of the Fancy Pants games, lamenting over their lack of quality. Each game since the first has progressed in variation, detail (like Squiggleville), and animation. Even for a stick figure, Fancy Pants Man has evolved significantly from his original incarnation.
Benevolent Architecture: Many of the locations just happen to be perfect for performing reality-defying stunts while still acting as a coherent platformer.
Bottomless Pits: In the first two games, falling into a pit immediately takes a life away. The second game's snail-shell can be lost to these pits, requiring Fancy Pants Man to reroute to put the snail shell in the golf hole. The third game is more infrequent and forgiving with bottomless pits, being nonexistent in primary levels.
Non-Lethal Bottomless Pits: In challenges that have bottomless pits, falling into one just returns Fancy Pants Man to a checkpoint without losing health or lives (though timed challenges will continue without making up for lost time).
Damn You, Muscle Memory: Thanks to a reconstructed physics engine, the physics in World 1 Remix and World 4 more 'floaty' than the physics in World 1, World 2, and World 3. This can lead to players failing to run through ledges where momentum in later games would allow them to do so.
Depth Perplexion: Some objects look like part of the foreground or background but can be interacted with, like the cardboard box in World 1 or the tree trunks in one of World 3's challenges.
Easter Egg: Starting in World 2, ducking several times in a row makes Fancy Pants Man make the "devil horns" gesture (giving the impression of headbanging).
In World 3, Fancy Pants Man can Goomba Stomp Rainbowbeard while he's in the middle of his speech. This causes him to immediately drop to the next stage.
Goomba Stomp: Fancy Pants Man's main method of dispatching enemies. Starting in World 2, stomping only stuns enemies, and he has to defeat them by running into them to kick them offscreen. World 3 has some microtrials where this is required.
Heroic Mime: Fancy Pants Man, barring the "Ow!" he makes when hit by an enemy.
Idle Animation: After being left around for a while, Fancy Pants takes a comb out of his pants and combs his hair, accidentally turning into an afro. After a longer while, he stretches, yawns, scratches his back, and eventually falls asleep.
Law of 100: Collecting 100 Squiggles gets Fancy Pants Man an extra life.
Losing Horns: The descending notes variation play upon the loss of a life.
Le Parkour: Exaggerated; not only can Fancy Pants Man wall-jump, perform backflips, and hop from platform to platform in the course of normal gameplay, World 2 has an area in level 5 where he runs continuously while completely upside down.
Playable Menu: The main menu is a small box where Fancy Pants Man can navigate and open the doors to the various sections of the game.
Time Trial: There is a speedrun timer in World 2 in the Trophies + Colors room, and microtrials count how quickly Fancy Pants Man completes them in World 3.
Trademark Favorite Food: Ice cream is first shown as the food of choice in World 2 as a Fancy Golfball reward. Newgrounds Rumble shows Fancy Pants Man being lured into the Newgrounds realm with a fake 'Free Ice Cream Day', and Cutie Pants requests rainbow-flavored ice cream in World 3.
Wall Jump: A staple ability of Fancy Pants Man unlocked in World 1. Starting in World 2, he can use this to slide up greased walls. "Why be realistic when you can be fancy?"
Wheel o' Feet: The unreleased, early versions of the first game had this in lieu of an actual running animation.
Smashing Hallway Traps of Doom: One specific section does this with ledges, where ending up squeezed between them depletes Fancy Pants Man of health. Thankfully, there are notches in these ledges where he can remain safe while he jumps to the next one.
And Your Reward Is Edible: Double-subverted: The mayor of Squiggleville offers ice cream for Fancy Pants Man's Fancy Golfball skills, but it gets stolen by the Angry Rabbit. Fancy Pants Man then spends the rest of the game getting back that ice cream.
Adaptation Induced Plot Hole: The online Flash version's Nutty Squirrel rewards Fancy Pants Man with "a squirrel-y prize", which is a dark-green pair of pants. How is that squirrel-y? The console versions have instead as a reward an acorn-shaped hat, much more relative to squirrels than a forest-like green.
Be The Ball: In multiplayer, a player can kick another player crouched into a ball to get him or her significant height and speed.
Rolling Attack: Possible to do as well, even in single-player by rolling down a slope.
Brick Joke: The Bat-Spider from World 2 returns with a role in the game.
Broken Bridge: The pyramid of enemies in the pirate ship prevents Fancy Pants Man from continuing the game until he reroutes to find a weapon suitable for falling them.
Captain Colorbeard: Parodied with Rainbowbeard. He, other than his initial name, dyes his hair and calls himself Captain Manly Beard.
Charged Attack: The longer the player holds down the attack key, the more Fancy Pants Man charges the swing from his pencil, and the more damage it will do to enemies. For aerial attacks, the duration of the attack extends as well, which can be improvised as a Double Jump or a way to remain in air.
Creator Cameo: Brad Borne (or at least, his speech bubble) appears in the third game when Fancy Pants Man takes the pencil Borne had out to draw World Four.
Cute Bruiser: While annoying and distressed at first, Cutie Pants is no slouch in following her brother's fanciness.
The console's tutorial, thanks to players trying to rush through it, has a part where Fancy Pants Man is meant to run and slide past a dummy enemy. Many players who do not take the time to read just end up being knocked back and running past it with Mercy Invincibility. Borne gives a Player Nudge in the PC version, where the ceiling of the area is too low to just run past, so the player must slide to continue.
It's entirely possible to finish Pirate Cove without going through half of it. After Fancy Pants Man collects the pencil, he can return through the entrance rather than continue upwards. It might not be entirely obvious that the 'dead end' in the area can be broken by using the pencil.
Invisible Block: Squiggles line invisible blocks in Ninfestation that lead to a hidden star.
It's All Upstairs From Here: The level section that leads up to Cutie Pants. When Fancy Pants Man eventually reaches her, a Trap Door is opened, undoing all of his progress and forcing him to find another way to reach her.
Loads and Loads of Loading: Present; while the loading screens aren't too long, moving from one area to another rather frequently compound the time waited at these screens.
Meaningful Background Event: A bunch of springs, Squiggles, and a star can be seen in the background of the latter half of Squiggleville. They correlate with an accessible, but inconspicuous area.
Pirate Girl: Cutie Pants, and not just because she gets captured by them.
Power Dyes Your Hair: Inverted, as when Rainbowbeard dyes his hair, he becomes (or at least, feels) more powerful.
Socialization Bonus: Some material in each level that are relatively difficult in single-player become trivial when multiple people join and interact; for example, jumping on another person to get to a star that's just out of reach rather than starting from a distance away and timing jumps for maximum height.
The Spiny: Some spiders (and pirates, some of the time) cannot be Goomba Stomped upon easily; this encourages use of the pencil, which is easier to use than a fast jump or slide.
Spoiled Brat: After Cutie Pants usurps the pirate ship's control, she asks for lollipop swirl gowns, unilammas, rainbow-flavored ice cream, among a 1200-number long list of wants.
Super Not-Drowning Skills: In the Pirate Cove, Fancy Pants Man never needs air when he's diving. Borne says that this was intentional, as he wanted the water level to be fun, rather than as a Scrappy Level. invoked
Temporary Platform: Thin sand platforms in Bummin' It Beach crumble when Fancy Pants Man steps on them. The thicker ones, oddly, do not.
Thundering Herd: The big cloud of pirates that decide on kidnapping Cutie Pants as their new captain.
Unmoving Plaid: Justified for the more complex colors of pants, as animating every stripe and dot at 30 frames per second would be incredibly difficult.
Unwanted Rescue: Cutie Pants finds reigning over pirates better than she thought; she repeatedly demands that she won't return home. After all, why would she be subject to Fancy Pants Man's annoyance when she could have independence at her whim?